{
  "QueryLanguage": "JSONata",
  "StartAt": "AcquireLock",
  "States": {
    "AcquireLock": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:putItem",
      "Arguments": {
        "TableName": "LocksTable",
        "Item": {
          "lockId": {
            "S": "{% $states.input.customerId %}"
          },
          "executionId": {
            "S": "{% $states.context.Execution.Id %}"
          },
          "expiresAt": {
            "N": "{% $string($toMillis($now()) + 900000) %}"
          }
        },
        "ConditionExpression": "attribute_not_exists(lockId) OR expiresAt < :now",
        "ExpressionAttributeValues": {
          ":now": {
            "N": "{% $string($toMillis($now())) %}"
          }
        }
      },
      "Assign": {
        "customerId": "{% $states.input.customerId %}"
      },
      "Output": "{% $states.input %}",
      "Retry": [
        {
          "ErrorEquals": [
            "DynamoDB.ConditionalCheckFailedException"
          ],
          "IntervalSeconds": 5,
          "MaxAttempts": 12,
          "BackoffRate": 1.5,
          "JitterStrategy": "FULL"
        }
      ],
      "Catch": [
        {
          "ErrorEquals": [
            "DynamoDB.ConditionalCheckFailedException"
          ],
          "Assign": {
            "customerId": "{% $states.input.customerId %}",
            "lockError": "{% $states.errorOutput %}"
          },
          "Next": "LockUnavailable"
        }
      ],
      "Next": "DoProtectedWork"
    },
    "DoProtectedWork": {
      "Type": "Task",
      "Resource": "arn:aws:states:::lambda:invoke",
      "Arguments": {
        "FunctionName": "arn:aws:lambda:us-east-1:123456789012:function:ProcessCustomer:$LATEST",
        "Payload": "{% $states.input %}"
      },
      "Output": "{% $states.result.Payload %}",
      "Catch": [
        {
          "ErrorEquals": [
            "States.ALL"
          ],
          "Assign": {
            "workError": "{% $states.errorOutput %}"
          },
          "Next": "ReleaseLock"
        }
      ],
      "Next": "ReleaseLock"
    },
    "ReleaseLock": {
      "Type": "Task",
      "Resource": "arn:aws:states:::dynamodb:deleteItem",
      "Arguments": {
        "TableName": "LocksTable",
        "Key": {
          "lockId": {
            "S": "{% $customerId %}"
          }
        },
        "ConditionExpression": "executionId = :execId",
        "ExpressionAttributeValues": {
          ":execId": {
            "S": "{% $states.context.Execution.Id %}"
          }
        }
      },
      "Retry": [
        {
          "ErrorEquals": [
            "States.ALL"
          ],
          "IntervalSeconds": 1,
          "MaxAttempts": 3,
          "BackoffRate": 2.0
        }
      ],
      "Next": "CheckWorkResult"
    },
    "CheckWorkResult": {
      "Type": "Choice",
      "Choices": [
        {
          "Condition": "{% $exists($workError) %}",
          "Next": "WorkFailed"
        }
      ],
      "Default": "Done"
    },
    "WorkFailed": {
      "Type": "Fail",
      "Error": "{% $exists($workError.Error) ? $workError.Error : 'WorkFailed' %}",
      "Cause": "{% $exists($workError.Cause) ? $workError.Cause : 'Protected work failed' %}"
    },
    "Done": {
      "Type": "Succeed"
    },
    "LockUnavailable": {
      "Type": "Fail",
      "Error": "LockContention",
      "Cause": "{% 'Could not acquire lock for ' & $customerId & ' after retries' %}"
    }
  }
}